Lay out the tiles on the floor without mortar to determine how the pattern will fit into the room.
Locate the corner farthest from the door, and set a larger of the two tiles into the corner. Place a smaller tile directly in front of it, and next to the wall to your left. Place a second, smaller tile to the right of the large tile, lining it up with the front edge of the large tile, so the small and large tiles are on the same plane.
Place a second large tile directly beside the first small tile and the first large tile. The second large tile should move off both the first large tile and the second small tile into the room at a diagonal toward the other end of the room. There should be a gap between this larger tile and the wall to your left. Cut a tile to fit into this gap, adjoining the smaller tile.
Look to the right of the first, large tile. There should be a gap between the wall and the second smaller tile. Cut a large tile to fit this space; it should extend out past the smaller tile by a half tile. Set a small tile next to this rectangular tile, and a full, uncut, large tile next to this smaller tile.
Set a large tile next to the second small tile, and the cut tile and smaller tile that are against the wall. This will start to form the second row of tiles in the pattern. Repeat this sequence, moving out to the right and into the room, cutting every other large tile against the wall to fit. The end result should be alternating large and small tiles that move in a diagonal across the room.
Take the tiles up from the floor in the opposite order you laid them down, and number them in reverse order so you can recreate the pattern.
Spread a small amount of thin set mortar onto the floor with a trowel, and replace the tiles in the hopscotch pattern. After you install a small section, lay out the next section, make your cuts, and remove the tiles to spread more mortar. Step back from the installation frequently to ensure that the pattern looks correct.
Wait 24 hours after you install all the tiles for the mortar to dry, then grout the tiles. Use a float to pack the mortar between the tile joints, and sponge away the excess grout after 10 minutes. Wait 24 hours before you use the floor.